如何在php/mysql中获取列名和结果集？

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);

// 检查连接
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

// 查询表
$sql = "SELECT * FROM myTable";
$result = mysqli_query($conn, $sql);

// 获取列名
$fields = mysqli_fetch_fields($result);

// 输出列名
foreach ($fields as $field) {
    echo $field->name . "<br>";
}

// 查询表
$sql = "SELECT * FROM myTable";
$result = mysqli_query($conn, $sql);

// 获取结果集
$rows = mysqli_fetch_all($result, MYSQLI_ASSOC);

// 输出结果集
foreach ($rows as $row) {
    echo $row["column_name"] . "<br>";
}

mysqli_close($conn);